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It is with interest that we read the paper by Buiten et al. (1) in
which the authors, using the implantable cardioverter defibrillator (ICD)
remote monitoring function in patients enrolled in the ICD-2 trial, showed
that hemodialysis (HD) is a trigger for atrial fibrillation (AF) episodes.
The study of Buiten confirms some observations we made in the recent past.
Few years ago we studied, by high frequency electrocardiograp...

It is with interest that we read the paper by Buiten et al. (1) in
which the authors, using the implantable cardioverter defibrillator (ICD)
remote monitoring function in patients enrolled in the ICD-2 trial, showed
that hemodialysis (HD) is a trigger for atrial fibrillation (AF) episodes.
The study of Buiten confirms some observations we made in the recent past.
Few years ago we studied, by high frequency electrocardiography, the
effects of the HD session on P-wave duration (Pwd), an expression of intra
-atrial conduction velocity, demonstrating that the procedure induced a
prolongation of Pwd closely related to the reduction of the plasma
potassium concentration. When the pre-and post-dialysis values of
electrolytes were put in a computational model that simulates the atrial
action potential, the atrial potential upstroke was slowed down from the
beginning towards the end of the HD session. Also we observed a reduction
of the effective refractory period (2). It is well known that both
phenomena are part of the electrical remodeling at the base of AF onset.
These data were also confirmed by a multiscale computer model (3). Buiten
et al. show that a lower concentration of potassium in the dialysis bath
(which usually is associated to a high shift of the electrolytes during
the dialysis session) is associated with a higher probability of
occurrence of AF episodes intra and peri-HD session. This observation is
concordant with our data. Recently, we reported a case of a patient in
whom HD session constantly induced episodes of paroxysmal AF. The episodes
were preceded by a reduction of the plasma potassium levels and an
increase of supraventricular ectopic beats and of the vagal component of
heart rate variability as evaluated by spectral analysis. The
computational model, feeded with the data of each session, consistently
showed an increase in atrial potential upstroke duration and a reduction
in the effective refractory period. Both phenomena were enhanced when the
IK,ACh current, sensitive to acetylcholine, was added to the model,
suggesting that the vagal rather than adrenergic stimulation plays an
important role in the genesis of intradialytic AF episodes (4). We think
that it would be very interesting to test this hypothesis using data
obtained from the remote monitoring of ICD-2 trial patients.